import fs from 'node:fs'
import crypto from 'node:crypto'
import { EventEmitter } from 'node:events'

class PersistentFile extends EventEmitter {
  constructor({ filepath, newFilename, originalFilename, mimetype, hashAlgorithm }) {
    super()

    this.lastModifiedDate = null
    Object.assign(this, { filepath, newFilename, originalFilename, mimetype, hashAlgorithm })

    this.size = 0
    this._writeStream = null

    if(typeof this.hashAlgorithm === 'string') {
      this.hash = crypto.createHash(this.hashAlgorithm)
    } else {
      this.hash = null
    }
  }

  open() {
    this._writeStream = fs.createWriteStream(this.filepath)
    this._writeStream.on('error', (err) => {
      this.emit('error', err)
    })
  }

  toJSON() {
    const json = {
      size: this.size,
      filepath: this.filepath,
      newFilename: this.newFilename,
      mimetype: this.mimetype,
      mtime: this.lastModifiedDate,
      length: this.length,
      originalFilename: this.originalFilename,
    }
    if(this.hash && this.hash !== '') {
      json.hash = this.hash
    }
    return json
  }

  toString() {
    return `PersistentFile: ${this.newFilename}, Original: ${this.originalFilename}, Path: ${this.filepath}`
  }

  write(buffer, cb) {
    if(this.hash) {
      this.hash.update(buffer)
    }

    if(this._writeStream.closed) {
      cb()
      return
    }

    this._writeStream.write(buffer, () => {
      this.lastModifiedDate = new Date()
      this.size += buffer.length
      this.emit('progress', this.size)
      cb()
    })
  }

  end(cb) {
    if(this.hash) {
      this.hash = this.hash.digest('hex')
    }
    this._writeStream.end(() => {
      this.emit('end')
      cb()
    })
  }

  destroy() {
    this._writeStream.destroy()
    const filepath = this.filepath
    setTimeout(function() {
      fs.unlink(filepath, () => {})
    }, 1)
  }
}

export default PersistentFile
